Improvement in pocket sun-dials



H. H. HEMPLER.

, Pocket Sun Dial. No. 48,812. Patented July 18, 1865.

UNITED STATES PATENT OFFICE.

HENRY H. HEMPLER, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN POCKET SUN-DIALS.

Specification forming part of Letters Patent No. 48,812, dated July 18,1865.

To all whom it may concern Be it known that I, HENRY H. HEMPLER, of thecity of \Vashington, District of Columbia,haveinvented a new andImproved Pocket Sun-Dial; and I do hereby declare that the following isa full and exact description thereof, reference being bad to theaccompanying drawings andthe letters of reference marked thereon.

In the drawings, Figure 1 is a plan view. Fig. 2 is an elevation showingthe gnomon or index, and Fig. 3 shows the dial when folded.

The nature of my invention consists in constructing a portable or pocketsun-dial of an economical and convenient form for readily as certainingthe time of the day. It is not liable to get out of order, is very lightand small, and can be carried in the vest-pocket without anyinconvenience.

To enable others skilled in the art to make and use myinvention, I willproceed to describe its construction and operation.

I construct the dial of two plates or leaves, of metal or other suitablematerial, connected together by means 'ot' a central hinge or joint, soas to fold toget er, as shown at A, Fig. 3. To this central hin thegnomon or index of thedial is attached, s as to be inclosed between theleaves of the dial when folded together and to stand up at 'ht anglesthereto when opened or spread out flat. This is effeeted by a smallprojection or lug, b, Fig. 3, which is attached to the under side of thehinge, so as to be nipped orclasped between the interior edges of thejointed plates or leaves, when they are unfolded or spread out. By thisarrangement the index and the dial-plates mutually support each other,the log on the hinge serving to prevent the leaves from being openedbeyond a plane or a flat surface, andat the same time, when so opened,preventing theindexitself from beingturned to either side, or, in otherwords, holding it in a vertical position.

On the inside of the plates or leaves I graduate or mark in the usualway the lines and figures which constitute the dial. To one of theplates I attach a small compass for the purpose of enabling the observerto place the index in the line of the meridian. This compass may be sunkwithin the plate to which it is attached, as shown at 0, Fig. 1.

I propose, if desirable, to apply to the index an adjustable or slidingplate, pivoted at the lower end thereof, and so graduated at its outerend that its variable elevation will correspond with the declination ofthe sun at different latitudes, and thus form a correction of the edgeof the shadow, as is clearly shown in the drawings at B, Fig. 2.

The operation of my instrument is as follows: When I wish to find thetime of day I unfold the plates, set the gage with the latitude 1 am in,let the compass point to the N, as shown on the dial at G, and the edgeof the shadow striking over the index on or between the lines andfigures denotes the time of the day.

\Vhat I claim as my invention, and desire to secure by Letters Patent,is-

A portable sun-dial with hinged or folding plates and central index, incombination, substantially in the manner herein described.

HENRY H. HE MPLER.

Witnesses:

T. R. BYRNE, R. B. OWENS.

